The METEOSAT Third Generation (MTG) Programme will provide the geostationary platforms for operational
meteorological data acquisitions over Europe in 2018-2030. The Flexible Combined Imager (FCI) instrument is one of
the MTG imager instruments and has a heritage from SEVIRI flown on the current METEOSAT Second Generation
(MSG) satellites. It is a radiometer providing measurements in 16 spectral bands with a full Earth coverage every 10
minutes. For the Level 2 processing of FCI datasets the measurements have to be re-sampled on a constant reference grid
in a geostationary projection – this process is referred to as rectification.
The use of a three-axis stabilised platform and the scanning scheme applied to the FCI make rectification in MTG more
challenging than in the MSG/SEVIRI case. Classical interpolation formulas assume a uniform sampling spacing of the
measurements. However, non-uniform sampling may occur in the FCI sampling acquisition due to platform dynamics,
micro-vibrations, thermo-elastic focal plane and optical distortions. In such a case, classical methods can cause
significant rectification errors and interpolation algorithms, which can cope with non-uniform sampling, are required.
This paper analyses the effect of non-uniform sampling in the FCI rectification process and aims to select and assess
suitable resampling algorithms for the FCI L1 processing chain. Several techniques tailored to non-uniform resampling
have been implemented. Performances of both uniform and non-uniform interpolation algorithms have been evaluated
and compared using simulated FCI-like data samples. The analysis has been done for a nominal and a worst-case sample
acquisition scenario. The presentation will show the results of our simulations with respect to the MTG requirements.